https://www.truck-manuals.net/mack/ OPERATION 137 STARTING THE VEHICLE General Information Before putting the key in the ignition switch, set the parking (spring) brake, disengage the clutch (if equipped) and put the transmission in NEUTRAL.
CAUTION Do not engage the starting motor too soon after an incomplete start of the engine, or the starter may be damaged. Wait at least five seconds before attempting to restart the engine.
CAUTION If the engine does not start immediately, limit cranking periods to 30 seconds to avoid overheating and damaging the starter.
CAUTION Do not rev the engine at start-up. Turbocharger damage may result because lubricants need time to establish a film between moving parts.
Push Button Starters Put the key in the ignition switch. Turn the key clockwise to the first "click" (about two o’clock position) to activate the instruments. Depress the starter button and release as soon as the engine starts. Keep the clutch (if equipped) disengaged until the engine runs smoothly.
